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Nov. 18, 1930. .1. A. McGlNNls SLUG CASTING MACHINE Filed May 27, 192'? Patented Nov. 18, 1930 UNITED STATES PATENTol-FICE JOHN A. MCGINNIS, OF WHEELING, WEST VIRGINIA, .ASSIGNOR TO WHEELING STAMP- ING COMPANY, OF WHEELING, WEST VIRGINIA, A CORPORATION OF WEST VIR- GINIA.

SLUG-CASTING MACHINE Application med May 27,

This invention relates to slug casting mechanisms such, for instance, as that shown in my joint application with Walter T. Davis, Serial Number65,351, filed October 28, 1925, and relates more especially to the casting of slugs to be used in the' manufacture of collapsible tubes.

Collapsible tubes are formed of relatively soft metal which melts at a relatively low temperature, and which, when melted oxidizes to some extent upon exposure to the air. This metal is usually a well-known tin composition.

According to one method for the manufacture of collapsible tubes, the metal is melted in a pot, and is cast in a casting ma chine of the type referred to in my said copending joint application above mentioned into slugs or buttons. These slugs or buttons are then used in the extrusion presses. The castingpof the slugs or buttons is accomplished by flowing a predetermined quantity of molten metal in succession into a series of molds, the feeding being controlled by a valve which is intermittently operated in timed relation with the series of molds.

Heretofore, considerable difficulty has been encountered in the operation of the casting machines by reason of the fact thatthe metal oxidized in the valve passages and around the discharge opening of the casting valve, the oxide or dross collecting i-n the valve and the valve passages. After the machine had operated for a few hours, it was necessary to stop it, and clean out the valves and remove the dross from the valve passages and around the discharge orifice, as the accumulation of dross prevented the proper quantity of metal from flowing into the molds. Some of the dross would also get-into the buttons of metal being cast and produce impurities, which, when the button was extruded to form a thin collapsible tube, rey sulted in the production of an imperfect tube. There was also considerable friction and wear in the valves by reason of the accumulation of dross therein.

According to the present invention there is provided means whereby oxidation of the metal in and about the casting valve is pre- 1927. Serial No. 194,680.

trates one embodiment of a casting valve to i which my invention is applied, and-in which- Figure 1 is a top plan view of a double valve construction wherein parts of one ofthe valves is shown in section;

1Figure 2 is a transverse vertical section in the plane of line II-II of Figure 1; and

Figure 3 is a detail view of one of the valve plugs, the view being partly in section and partly in elevation.

In the machine shown in my said joint application with Walter T. Davis, the casting y machine is provided with two valves which are close together and which deliver metal to the same revolving casting disc in which there is a series of mold cavities. Since the present invention is adapted for use on a machine of the type shown in said application, I have illustrated a double casting valve, but the invention is not limited to the number of valves, being applicable to one or more, according to the number of valves that are found desirable or necessary.

In the drawings, 2'designates the melting pot, 3 is a supporting table, and 4 is a revolving casting disc having a plurality of mold cavities 5 in the periphery thereof. The oo nstruction and operation and general arrangement of the melting pot, table and casting disc is shown in the said co-pending joint application, and forms no part of the present invention.

Secured to the bottom of the pot 2 at any suitable location is a casting 6 forming a valve body and having a passage 7 therein that communicates with the interior of the melting pot 2, as clearly shown in Figure 2. Set into the casting 6 are valve bushings 8 which have a tapered bore therethrough. Set into each of the tapered bushings is a tapered valve plug 9, the valve plug 9 being adapted to rotate in the bushing. Supported on the front of the casting 6 by means of bolts 10 and spacers 11V bearing member 15 supported in the bracket 12. On each of the shafts 13 is a crank 16 by means of which the valve is rotated through an arc of substantially 90, by any suitable mechanism, such for instance as that shown in the said co-pending application.

Secured to the reduced end portion 14 of the shaft 13 of each of the valves is a. rod 17 about which is a compression spring 18. The compression spring bear-s against a washer 19 at the end of the reduced portion 14 of the shaft, and is confined by the end of the bearing element 15. 'Ihe end of the rod 17 projects through the end of the bearing member 15 and is provided with a nut 2O which is threaded thereon. The spring 18 exerts a pressure which forces the plug 9 into the tapered bore of the bushing, while the nut 20 limits the action of the spring.

The valve 9 is of the usual plug type, having a single diametrically extending opening 21 therethrough. Each of the bushings 8 has an opening 22 therein which is inclined upwardly, and which communicates with a passage 23 leading upwardly into the passage 7. In the top of each of the bushings 8 is a vent port 24 communicating with a passa-ge 25 in the valve plug. In the bottom of each of the bushings 8 is a discharge port 26 which communicates with the discharge passage 27 at the bottom of the `casting 6. Communicating with the vent passages 25 are pipes 28 through which a non-oxidizing gas can be supplied to the valve in -place of air for venting the valve. Ordinary natural gas or ordinary artificial gas is satisfactory, and the pipes 28 may be connected with the same pipes 29 that supply the-usual burners 3() provided around the outside of the valve for keeping the valve hot as shown in the said co-pending application. v

When thevalve 9 is rotated through an arc of 90, the passage 21 is brought into register with the inclined passage 22. Metal can flow from the pot through the passage 7 and through the passage 22 into' the passage 21 in the valve. Any gas which i-s in the passage 21 will be displaced by the metal and the gas will bubble up through the metal. Since the gas is a non-oxidizing gas, it will not injure the metal by bubbling through it.

When the passage 21 has filled with metal, and the valve rotates 90 in the opposite direction, the metal willabe discharged through the discharge opening 27 into the mold cavities 5 in the disc 4, the mold cavities being brought into register with the discharge openings of the valves. When the metal flows out of the valves, the valves will be vented by gas supplied through the pipes 28 instead of by air'as heretofore has been the practice. This prevents the entrance of oxidizing gases into the valve and avoids the accumulation of dross and oxides in and about the valve and valve passages. Since the valve passages are kept free of dross and oxides, the slugs or buttons which are cast will be kept pure, even when the machine is operated continuously for hours at a time. Ithas been found that Where gas is supplied to the casting valves instead of air, that the machine will operate day after day through each working day Without attention to the valves, whereas, when air was used the valves had to be cleaned several times during' the day, and many of the slugs which were cast were imperfect.

, Due to the fact that air is excluded from the valve, and that there is no tendency for dross and oxides to accumulate in the valve,

the valve can operate more loosely in its seat. Y The nut 20 is adjusted so that the plug 9 is not tight in the seat and some of the gas which is supplied through the passages 25 will escape around the plug, preventing the entrance of air, allowing the valve to work loosely, and to some extent cushion the valve in its seat. A nice operating adjustment for the valves can be obtained by reason of the nut 20 opposing the action of the spring 18.

Each of the valve plugs is preferably provided -with a co-axially extending screw 31, best shown in Figure 3, which is entered into the free end of the valve plug and whose terminal can be projected in the valve passage 21. By setting the screw 31 in, the metal 'holding capacity of the passage 21 is reduced and by setting it out its capacity is increased. This provides an adjustment by means of which the weight of the metal cast into each button can be very accurately adjusted.

The advantages of the invention reside in providing means for excluding oxidizin gases from the valves and valve passages an in the provision of means for supplying a nonoxidizing gas thereto.

Further advantages reside in the provision of adjusting means on the valve so that the wear between the valve and the seat for the valve can be minimized and at the same time the accumulation of dross and oxides around the valve prevented.

While the invention has been specifically described in connection with a double casting valve it will be understood that it is not limited to use with a double valve. It will also be understood that various changes and modifications may be made in the particular construction and arrangement of parts Within the spirit of my invention and under lthe scope of the'following claims.

I claim: l

1. In a slug casting machine, a hot metal Cil holder, a casting valve having a hot metal receiving opening therein for intermittently dispensing a measured quantity of metal from the holder, and means for supplying a non-oxidizing gas to the opening in the valve.

2. In a slug casting machine, a hot met-al holder, a valve for intermittently discharging a measured quantity of metal from the holder, the valve ,being in communication with the holder through an inclined passage, said valve being movable from a metal receiving position to a metal discharging position, a source of non-oxidizing gas connected with the valve for supplying gas thereto when it is in metal discharging position, said gas contained in the valve being allowed to escape through the said inclined passage when the valve is in metal receiving position.

3. In a slug casting machine, a hot metal holder, a valve having a metal holding cavity therein for intermittently dispensing a predetermined quantity of metal from the iolder, said valve being movable from a metal receiving position at which time the cavity is in communication with the, holder to a metal discharging position at which time the metal in the cavity can be discharged, and means for supplying a nonoXidizing gas to the valve cavity when the valve is in discharging position.

4. In a slug casting machine, a valve therefor including a valve body having a valve seat therein, a valve plug rotatable in the seat having a metal receiving cavity therein, means for rotating the valve, a discharge port in the valve body, a metal receiving port in the valve body, a vent port in the valve body opposite the discharge port, and a gas pipe connected with the vent port.

5. In a slug casting machine, having a hot metal holder and a valve for controlling the flow ofmetal from the'holder, means for supplying a non-'oxidizing gas to the interior of the valve to prevent the accumulationor` K dross therein.

k6.. In a slug casting machine, a valve therefor including a valve body havinga tapered valve receiving passage therein, a valve plug seated in the passage, said plug having a bore therethrough, ports in the valve body adapted to communicate with the bore in the valve plug upon rotation of the valve plug, means for venting the valve with gas, resilient means for urging the valve plug into the tapered passage, and means for adjustably limiting the movement of the plug into the passage whereby the plug may be kept suficient-ly loose in the passage to allow for a restricted circulation of gas thereabout.

7 In a slug casting machine, a hot metal i holder, a rotatable plugtype valve for intermittently delivering a measured quantity of metal from the holder, said valve including a body having a tapered seat and a plug for cooperation with the seat, means for adjustin and a rotatable valve plug cooperating with the seat, means for resiliently urging of the plug against the sea-t, means for limiting the engagement of the plug against the seat, said plug having a metal receiving cavity eX- tending therethrough, a metal supply passage leading from the holder to the valve seat, a discharge passage at substantially right angles to the delivery passage, and a gas supply passage substantially opposite the discharge passage, said gas supply passage being adapted to blow gas through the valve and out the discharge opening when the valve plug is in discharge position, and to circulate gas about the valve plug when the cavity in the plug is communicating with the metal supply passage.

9. In a slug casting machine, a hot metal holder, a valve structure for intermittently discharging a measured quantity from the holder, said valve structure having a discharge, and means for supplying a non-oXi-.

dizing gas through the valve to prevent oxidation of the metal in the valve, and means for creating a non-oxidizing atmosphere about the discharge of the valve.

10. The method .of forming non-ferrous cast articles which comprises the steps of filling a closed measuring receptacle with a non-oxidizing gas, then filling the measuring receptacle with molten metal Jfrom a source .of supply without permitting air /to contact with the moltenmetal flowing from the supply to the measuring receptacle and displacing the non-oxidizing gas in the measuring receptacle by the molten metal, and then delivering the molten metal in the measuring receptacle to a mold and admitting non-0X- idizing gas into the measuring receptacle as the molten metal passes therefrom, to prevent air from contacting with the molten metal between the source ofsupply and the time it is delivered from the measuring receptacle.

In testimony whereof I have hereunto set JOHN A. MCGINNIS.

my hand. 

